The present invention relates to fuel tank closures. More particularly, the present invention relates to a fuel tank closure having a housing assembly and a seal coupled to the housing assembly. The seal is positioned to engage a tank filler neck to provide a sealed closure of the tank filler neck.
A fuel cap for a filler neck a vehicle fuel system includes an upper housing and a lower housing configured to be inserted into the filler neck. The upper housing and lower housing are cooperatively configured to allow both rotational and axial relative movement with respect to one another.
A seal is positioned to lie between the lower housing and the filler neck, thereby creating a seal when the fuel cap is moved to a tightened position. A spring mount is coupled to the lower housing. A spring, preferably a compression spring, engages both the spring mount and the upper housing to bias the lower housing axially toward the upper housing. This bias assists in loosening contact of the seal and filler neck during removal of the fuel cap.
In preferred embodiments, a cam and cam follower connection is provided between the upper and lower housing. The cam and cam follower connection includes at least one cam arranged on an upper surface of the lower housing and positioned on the upper surface so that the cam slopes upward toward the upper surface to engage a cam follower depending from a lower flange of the upper housing. In other embodiments, these locations may be reversed: the cam may be configured on the upper housing and the cam follower may be configured on the lower housing. In either embodiment, the cam and cam follower cooperate to generate relative axial movement as the upper housing is rotated relative to the lower housing.
Each cam includes a wall at a lower end of the cam and a detent formed adjacent an upper end and configured to receive a lower end of the cam follower.
The cap includes at least one lug extending radially outwardly from the outer surface of the lower housing. Each lug engages a respective notch in the filler neck when the cap is moved to the tightened position to prevent rotation of the lower housing relative the filler neck when the cap is in the tightened position.
Additional features of the invention will become apparent to those of ordinary skill in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.